Getting Started

The pins package helps you publish data sets, models, and other Python objects, making it easy to share them across projects and with your colleagues. You can pin objects to a variety of “boards”, including local folders (to share on a networked drive or with DropBox), RStudio connect, Amazon S3, Google Cloud Storage, and more. This vignette will introduce you to the basics of pins.

from pins import board_local, board_folder, board_temp, board_urls

Getting started

Every pin lives in a pin board, so you must start by creating a pin board. In this vignette I’ll use a temporary board which is automatically deleted when your Python session is over:

board = board_temp()

In real life, you’d pick a board depending on how you want to share the data. Here are a few options:

board = board_local() # share data across R sessions on the same computer
board = board_folder("~/Dropbox") # share data with others using dropbox
board = board_folder("Z:\\my-team\pins") # share data using a shared network drive
board = board_rsconnect() # share data with RStudio Connect

Reading and writing data

Once you have a pin board, you can write data to it with the .pin_write() method:

from pins.data import mtcars

meta = board.pin_write(mtcars, "mtcars", type="csv")
Writing pin:
Name: 'mtcars'
Version: 20220624T192139Z-3b134

The first argument is the object to save (usually a data frame, but it can be any Python object), and the second argument gives the “name” of the pin. The name is basically equivalent to a file name; you’ll use it when you later want to read the data from the pin. The only rule for a pin name is that it can’t contain slashes.

Above, we saved the data as a CSV, but depending on what you’re saving and who else you want to read it, you might use the But you can choose another option depending on your goals:

  • type = "csv" uses to_csv() from pandas to create a .csv file. CSVs can read by any application, but only support simple columns (e.g. numbers, strings, dates), can take up a lot of disk space, and can be slow to read.

  • type = "joblib" uses joblib.dump() to create a binary python data file. See the joblib docs for more information.

🚧 Data formats TODO 🚧

  • type = "arrow" uses arrow::write_feather() to create an arrow/feather file. Arrow is a modern, language-independent, high-performance file format designed for data science. Not every tool can read arrow files, but support is growing rapidly.

  • type = "json" uses jsonlite::write_json() to create a .json file. Pretty much every programming language can read json files, but they only work well for nested lists.

After you’ve pinned an object, you can read it back with pin_read():

board.pin_read("mtcars")
mpg cyl disp hp drat wt qsec vs am gear carb
0 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4
1 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
2 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
3 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1
4 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2
... ... ... ... ... ... ... ... ... ... ... ...
27 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
28 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4
29 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6
30 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
31 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2

32 rows × 11 columns

You don’t need to supply the file type when reading data from a pin because pins automatically stores the file type in the metadata, the topic of the next section.

Note that when the data lives elsewhere, pins takes care of downloading and caching so that it’s only re-downloaded when needed. That said, most boards transmit pins over HTTP, and this is going to be slow and possibly unreliable for very large pins. As a general rule of thumb, we don’t recommend using pins with files over 500 MB. If you find yourself routinely pinning data larger that this, you might need to reconsider your data engineering pipeline.

Note

If you are using the RStudio Connect board (board_rsconnect), then you must specify your pin name as <user_name>/<content_name>. For example, hadley/sales-report.

Metadata

Every pin is accompanied by some metadata that you can access with pin_meta():

board.pin_meta("mtcars")
Meta(title='mtcars: a pinned 32 x 11 DataFrame', description=None, created='20220624T192139Z', pin_hash='3b134bae183b50c9', file='mtcars.csv', file_size=1333, type='csv', api_version=1, version=Version(created=datetime.datetime(2022, 6, 24, 19, 21, 39), hash='3b134'), name='mtcars', user={})

This shows you the metadata that’s generated by default. This includes:

  • title, a brief textual description of the dataset.

  • an optional description, where you can provide more details.

  • the date-time when the pin was created.

  • the file_size, in bytes, of the underlying files.

  • a unique pin_hash that you can supply to pin_read() to ensure that you’re reading exactly the data that you expect.

When creating the pin, you can override the default description or provide additional metadata that is stored with the data:

board.pin_write(
    mtcars,
    name="mtcars2",
    type="csv",
    description = "Data extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).",
    metadata = {
        "source": "Henderson and Velleman (1981), Building multiple regression models interactively. Biometrics, 37, 391–411."
    }
)
Writing pin:
Name: 'mtcars2'
Version: 20220624T192139Z-3b134
Meta(title='mtcars2: a pinned 32 x 11 DataFrame', description='Data extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).', created='20220624T192139Z', pin_hash='3b134bae183b50c9', file='mtcars2.csv', file_size=1333, type='csv', api_version=1, version=Version(created=datetime.datetime(2022, 6, 24, 19, 21, 39, 228841), hash='3b134bae183b50c9'), name='mtcars2', user={'source': 'Henderson and Velleman (1981), Building multiple regression models interactively. Biometrics, 37, 391–411.'})
board.pin_meta("mtcars")
Meta(title='mtcars: a pinned 32 x 11 DataFrame', description=None, created='20220624T192139Z', pin_hash='3b134bae183b50c9', file='mtcars.csv', file_size=1333, type='csv', api_version=1, version=Version(created=datetime.datetime(2022, 6, 24, 19, 21, 39), hash='3b134'), name='mtcars', user={})

While we’ll do our best to keep the automatically generated metadata consistent over time, I’d recommend manually capturing anything you really care about in metadata.

🚧 Versioning

⚠️: Warning the examples in this section use joblib to read and write data. Joblib uses the pickle format, and pickle files are not secure. Only read pickle files you trust. In order to read pickle files, set the allow_pickle_read=True argument. See: https://docs.python.org/3/library/pickle.html.

⚠️: Turning off versioning is not yet implemented; all Python pins are versioned. These docs are copied from R pins.

In many situations it’s useful to version pins, so that writing to an existing pin does not replace the existing data, but instead adds a new copy. There are two ways to turn versioning on:

  • When you create a board you can turn versioning on for every pin in that board:

    board2 = board_temp(versioned = TRUE)
    
  • When you write a pin, you can specifically request that versioning be turned on for that pin:

    board2 = board_temp()
    board2.pin_write(mtcars, versioned = TRUE)
    

Most boards have versioning on by default. The primary exception is board_folder() since that stores data on your computer, and there’s no automated way to clean up the data your saving.

Once you have turned versioning on, every pin_write() will create a new version:

board2 = board_temp(versioned = True, allow_pickle_read=True)

board2.pin_write([1,2,3,4,5], name = "x", type = "joblib", title="TODO")
board2.pin_write([1,2,3], name = "x", type = "joblib", title="TODO")
board2.pin_write([1,2], name = "x", type = "joblib", title="TODO")
board2.pin_versions("x")
Writing pin:
Name: 'x'
Version: 20220624T192139Z-91544
Writing pin:
Name: 'x'
Version: 20220624T192139Z-331fd
Writing pin:
Name: 'x'
Version: 20220624T192139Z-40b4b
created hash version
0 2022-06-24 19:21:39 331fd 20220624T192139Z-331fd
1 2022-06-24 19:21:39 40b4b 20220624T192139Z-40b4b
2 2022-06-24 19:21:39 91544 20220624T192139Z-91544

By default, pin_read() will return the most recent version:

board2.pin_read("x")
[1, 2, 3, 4, 5]

But you can request an older version by supplying the version argument:

version = board2.pin_versions("x").version[1]
board2.pin_read("x", version = version)
[1, 2]

🚧 Reading and writing files

⚠️: pin_upload() and pin_download() are not yet implemented in Python. These docs are copied from R pins.

So far we’ve focussed on pin_write() and pin_read() which work with R objects. pins also provides the lower-level pin_upload() and pin_download() which work with files on disk. You can use them to share types of data that are otherwise unsupported by pins.

pin_upload() works like pin_write() but instead of an R object you give it a vector of paths. I’ll start by creating a few files in the temp directory:

# paths = file.path(tempdir(), c("mtcars.csv", "alphabet.txt"))
# write.csv(mtcars, paths[[1]])
# writeLines(letters, paths[[2]])

Now I can upload those to the board:

# board.pin_upload(paths, "example")

pin_download() returns a vector of paths:

# board.pin_download("example")

You should treat these paths as internal implementation details — never modify them and never save them for use outside of pins.

Note that you can’t pin_read() something you pinned with pin_upload():

# board.pin_read("example")

But you can pin_download() something that you’ve pinned with pin_write():

# board.pin_download("mtcars")

Caching

⚠️: board_url is not yet implemented in Python. These docs are copied from R pins.

The primary purpose of pins is to make it easy to share data. But pins is also designed to help you spend as little time as possible downloading data. pin_read() and pin_download() automatically cache remote pins: they maintain a local copy of the data (so it’s fast) but always check that it’s up-to-date (so your analysis doesn’t use stale data).

Wouldn’t it be nice if you could take advantage of this feature for any dataset on the internet? That’s the idea behind board_url() — you can assemble your own board from datasets, wherever they live on the internet. For example, this code creates a board containing a single pin, penguins, that refers to some fun data I found on GitHub:

my_data = board_urls("", {
  "penguins": "https://raw.githubusercontent.com/allisonhorst/palmerpenguins/master/inst/extdata/penguins_raw.csv"
})

You can read this data by combining pin_download() with read.csv()1:

fname = my_data.pin_download("penguins")

fname
['/home/runner/.cache/pins-py/http_e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855/e6ac0d2da33fad7e72df6b900933a691b89ed7d54ec0e4a36fe45c32d7e2f67e_penguins_raw.csv']
import pandas as pd

pd.read_csv(fname[0]).head()
studyName Sample Number Species Region Island Stage Individual ID Clutch Completion Date Egg Culmen Length (mm) Culmen Depth (mm) Flipper Length (mm) Body Mass (g) Sex Delta 15 N (o/oo) Delta 13 C (o/oo) Comments
0 PAL0708 1 Adelie Penguin (Pygoscelis adeliae) Anvers Torgersen Adult, 1 Egg Stage N1A1 Yes 2007-11-11 39.1 18.7 181.0 3750.0 MALE NaN NaN Not enough blood for isotopes.
1 PAL0708 2 Adelie Penguin (Pygoscelis adeliae) Anvers Torgersen Adult, 1 Egg Stage N1A2 Yes 2007-11-11 39.5 17.4 186.0 3800.0 FEMALE 8.94956 -24.69454 NaN
2 PAL0708 3 Adelie Penguin (Pygoscelis adeliae) Anvers Torgersen Adult, 1 Egg Stage N2A1 Yes 2007-11-16 40.3 18.0 195.0 3250.0 FEMALE 8.36821 -25.33302 NaN
3 PAL0708 4 Adelie Penguin (Pygoscelis adeliae) Anvers Torgersen Adult, 1 Egg Stage N2A2 Yes 2007-11-16 NaN NaN NaN NaN NaN NaN NaN Adult not sampled.
4 PAL0708 5 Adelie Penguin (Pygoscelis adeliae) Anvers Torgersen Adult, 1 Egg Stage N3A1 Yes 2007-11-16 36.7 19.3 193.0 3450.0 FEMALE 8.76651 -25.32426 NaN
my_data.pin_download("penguins")
['/home/runner/.cache/pins-py/http_e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855/e6ac0d2da33fad7e72df6b900933a691b89ed7d54ec0e4a36fe45c32d7e2f67e_penguins_raw.csv']

1

Here I’m using read.csv() to the reduce the dependencies of the pins package. For real code I’d recommend using data.table::fread() or readr::read_csv().